You've Arrived Half an Hour Late to Pick Up a Friend

You've arrived half an hour late to pick up a friend. She was scheduled to take an examination, and even if you speed on the way to the university, she will now lose at least twenty minutes of the time she needs to complete the exam. According to the authors, what is the best thing to say when you arrive?

A) "It's all my fault. I overslept. I'm really sorry."
B) "I brought you some coffee and donuts to make it up to you."
C) "It's only one exam, and you're doing well in that course so far, aren't you?"
D) "Don't tell me that you've never overslept."